Solar Electric Project

[hayden]

It has been a while since I have on TBN - I have been doing some research here and there to figure out if solar electric is a viable option for me. In the past TBN has always been a good source of info for these types of things so I figured I would start checking thru the posts here. MA has put in place a Solar power incentive program which aims to bring the cost of a solar system down - but from my calculations still not down enough to make it a feasible alternative to being on grid. At least not where I am located.

Does anybody have any links to where I could learn more about solar electric power? The Homepower magazine looks interesting - I will check that out.

Any other recommended reading to do - or companies that supply solar equipment?

BTW - I also ran across the thread where you had the pics of the new tractor Peter - pretty nice.

Hey Jim, good to hear from you.

Check out the Alternative Energy Store Solar Panels, Wind Generators, Solar Home Systems, Energy Efficient Appliances and Residential Panels.

 

[MarkV]

Hi Guys interesting thread. Peter, knowing little about using a system such as yours to power a house, can you run a whole house AC unit from a reasonable amount of solar panels? Here in the South AC has become a necessity as we get older.

I had an opportunity to meet a couple that had been living off of solar power for about 10 years and take a tour of their system. It was very interesting and they were very excited to be adding 2 additional panels which allows them to use a full size electric refrigerator for the first time. I think they said the upgrade was costing about 25K.

MarkV

 

[3RRL]

We've had our solar power system running for almost 2 years now.
You can check it out here. Solar Power System
It was built prior to starting the log home so the contractor would have power up there at an isolated build site. It's designed to allow running of all appliances in the home plus a shop, but we still have to watch carefully not to overload the system. So we are selective as to what is turned on and running at the same time.
To get an idea of what it's powering, you can check out this thread 3R Log Home and Barn Project
Our home is recently completed and we had a chance to run all the appliances and AC. So far so good, but as I said, we still need to be selective. I'm sure we will have a learning curve and adjustments to make.
I have yet to wire up the machine shop to see how that will work out.

Like Peter said, going solar off grid makes complete sense when their is no alternative, or if connecting to the grid is an absorbatent amount, as it was in our case. Adding to a home already connected might take years to offset the cost of installation, but worth it nevertheless for reasons stated. Alternatives include specific solar applications such as for the well pump or something like that, where the cost of installation is relatively minor, and there is a trade off on the electric bill.

 

[swines]

You may want to look at About Us; Zomeworks Passive Solar Products

Steve Baer has had a variety of passive solar products since the mid-'70s - including solar panel sun trackers.

I had SunBenders on two skylights in my old house and they worked great to add heat in the winter and shade the skylights in the summer.

 

[Foozle]

Interesting podcast at this link by an inventor who claims solar will be competitive with fossil fuels for energy generation within about 5 years. I hope he is correct.

Science Friday Archives: Will We Recognize The Future?

 

[saltman]

Thanks for the reassurance Hayden. I was pretty sure that a 4.5-6kw system would be plenty for very efficient 1700 sq home.
I will not have A.C. but will have a swamp cooler which should be efficient in a high desert climate.

Currently my cabin in this setting is 10-12 degrees cooler than the outside due to insulation and efficient windows. I was told that a swamp cooler will cool it another 20 degrees if the humidity is low. The high temp out there is 95 so I should be very comfortable.

3RRL you have the Utopia of Solar Power Systems from what I have seen. You have a large house and an A.C. unit but others here should't judge what their solar needs are from this example. Everyones needs are different as are our lifestyles.

Backwoods Solar Electric Systems gives different sizing comparisons and it looks like a normal family in a solar designed home should spend about 11,500 -18,500 without rebates. This to me seems very reasonable reguardless of how much it costs to hook up to the grid. The peace of mind of knowing I will always have reliable power and not be hit with blackouts and huge increases every year here in Southern California is well worth the investment. Plus I get a lot of satisfaction out of being totally self sufficient and non reliant.

 

[mjncad]

Nice work Hayden! I doubt all the conduit is going to affect 36" diameter concrete piers much, especially if you make a cage of rebar to boot.

Out of curiosity, did you miter the pipe's end that will be embedded in concrete, or provide a couple of pieces of heavy rebar run through a couple of holes in the pipe at right angles? That will insure the pipe can't twist in the concrete once the solar panel is installed and the wind interacts with the sail...err...panel.

 

[woodlandfarms]

We will to a tied system to our house in LA end of this year or beginning of next. Payback for my 69 charger that gets 8MPG

Our new house should be solar as well. Still working on those logistics and moneys...

One note is we are following this new technology of holographic solar panels. Lots of buzz in 06 and 07 but it has gone quiet in 08...

Holographic Solar: New Method of Concentrating Sunlight Could Be Cheaper : TreeHugger

 

[hayden]

OK, I'm back working on the solar power upgrade, and not a moment too soon. Another one of my Trojan L16H batteries developed a bad cell, so I had to disconnect one of the two battery banks. A dead cell raises all heck with the surviving cells causing them to overcharge while charging, and causing the good bank to discharge into the bad bank when not charging. The generator running in the middle of the night because the batteries were so low was the tip off that something was wrong.

This is the second of 8 batteries to develop a bad cell in the past 6 months, so they are clearly at the end of their life. I've been running them for 7, almost 8 years, so that's right about in the middle of the expected life for these batteries.

Anyway, back to the new system. I got 90% of the parts a few weeks ago, including the new 6KW 240V/120V inverter, 3.6KW of solar panels, dual charge controllers, and a whole host of breakers, wiring boxes, etc. I'm getting everything from the Alternative Energy Store, which is a great place.

The new batteries, which are 12 Surrette 4-KS-25PS 4 Volt, 1350AH are due to arrive tomorrow. These batteries will be tripple what I have now, and weigh 3700 lbs. I picked these particular batteries so I could have a single bank rather than two or more. It means fewer cells to maintain and water, and more reliable charging than parallel banks. However, their weight (315 lbs each) means they require end-to-end mechanical handling. We'll get to more on that later.

Today I spent building a battery box for these beasts. I had seriously considered buying a few of the metal job site tool chests that you may be familiar with to use as battery boxes, but in the end decided to build one out of wood. An insulated rather than conductive material is a nice safety precaution, and building a box I can keep it as compact as possible. Also, the basement where they will live has a low ceiling (only about 5 1/2'), and there needs to be clearance to lift a battery over the box edge and lower into the box without crashing into the floor joists. The batteries are 25" tall so there isn't a lot of wiggle room, and the job site boxes were a bit taller than I wanted.

The pictures are of the box at various stages of construction. It sure isn't fine cabinetry, but it serves the purpose. I'm polyurathaning the box inside and out to deter rot, and it will sit on 4 2x6 pressure treated skids on top of the crushed stone floor in the basement. This house is 200 yrs old, so the foundation is dry set granite blocks and a dirt floor. I've since mortered the joints in the walls and put down a vapor barrier and stone on the floor.

To get the batteries in and out of the box, I bought an engine hoist from TSC. This particular model has telescoping feet and boom so I can arrange it to reach far enough over the battery box to set the batteries in the second row even though the feet can't extend under the battery box as they would extend under a car. The only trick will be providing sufficient counter weight to lift the 300 lb battery without tipping over, but I think that's solvable. I'll have more on this tomorrow when I try it all out on a real battery in by garage. I want to be sure I can reach all the battery locations in the box before I haul everything down to the basement and try in while stooped over in cramped quarters.

 

[hayden]

The electronics are the new Xantrex XW components. It's a very nicely designed system with parts that integrate together better than anything else I've seen. It's also a split phase 120V/240V system out of the box. Other inverters require you to gang two together to get 240V and require external load sharing transformers, more breakers, more wiring, etc. The XW is a much cleaner design and installation.

Here's a picture of the major components layed out on a table, except the inverter itself is missing. It fits in the space in the upper right. All this will be mounted on a plywood power panel against pressure treated studs bolted to the foundation.

The one major thing I'm still waiting on are the solar panel mounting frames that go on top of the poles. They are due to ship next week, and I'm hoping to have everything else done and ready when the mounts arrive so I can mount the panels and go .

 

[ultrarunner]

Great project... keep the pictures coming.

Any chance of listing the components with prices after you get it up and running?

 

[hayden]

Any chance of listing the components with prices after you get it up and running?

Here are the major parts, but I'll leave out the prices since they are a moving target. Batteries, for example, have doubled in price since 3RRL did his system 2 years ago. You can find current prices and lots of other good info at the Alternative Energy Store (Solar Panels, Wind Generators, Solar Home Systems, Energy Efficient Appliances and Residential Panels). I'm and advisor to them and they are a great bunch of guys with great knowledge. By the way, I don't get paid as an advisor and have no economic interest in the company.

My system consists of:

24 Sharp 135W solar panels
2 Direct Power pole mounts (6" poles)
2 Midnite Solar combiner boxes
2 Lightning arestors
2 Xantrex XW MPPT charge controllers
4 60A CD breakers for the input and output for each charger
1 Xantrex XW 6048 6KW, 48V Inverter
1 Xantrex XW breaker panel and wiring box
1 Xantrex XW System Controller
1 Xantrex XW Generator controller
1 Xantrex XW gateway for computer monitoring
1 Battery desulfator (I forget the manufacturer)
1 pair 5' 4/0 battery cables
12 Surrette 4-KS-25PS 4V 1350Ah batteries wired in series for 1350Ah @48V

I've left out things like wire, conduit, and other site-specific nits, but it you want to know the details of the wire runs, loss calculations, wire sizing, conduit sizing, etc. I'd be happy to spill my guys on the subject.

I haven't picked the generator yet, but it will either be a Cummins 10KW diesel or a Kohler 10KW diesel. My current generator is an Onan 4kw propane model which has been great, but it's undersized for the new system and has 2500 hrs on it so I'll be retiring it. I have both bulk diesel and bulk propane on site, but I decided to go with diesel because of the overall higher efficiency of a diesel engine, especially at less than full load. I'll be using about 6KW while charging the batteries and at that load a diesel is about twice as efficient as a spark engine. Also, the smallest commercial grade 1800 RPM propane generator from Cummins (and I think Kohler too) is 20KW which is serious overkill for my needs.

The whole system will cost about $55k, with the panels, batteries, and generator (in that order) begin the biggest ticket items.

 

[ultrarunner]

Wow... thanks for the quick reply, materials list and ballpark system cost.

I will check Alternative Energy Store site.

One of my biggest hesitations is theft. Around my neck of the woods... metal theft is a big problem and the thieves seem to have no fear... I can just picture going away for a weekend and being looted.

I've even had the locks cut from my Cat D3 Dozer... not too sure how someone could steal my Dozer without getting caught...

Thanks Again!

 

[RedDirt]

For those thinking of solar water heating look into the "breadbox" design. In the 70's & 80's we lived both off grid and minimal grid for about fifteen years and found the breadbox design to be quite efficient and certainly reasonable and easy to build.

We used two naked 30gal discarded gas fired heater tanks laid horizontally, one above the other, piped in series; the lower one "feeding" the upper one. Cold piped to bottom tank, hot out the top tank. Tanks were placed in a six sided plywood box with a patio door "seconds" sheet of glass (cheap) top. Tanks were spaced about a foot apart and the inside of the box was insulated with foil-faced 1 1/2" or 2" rigid insulation that I sloped at calculated sun angles so sunlight was reflected to the back sides of the tank too. Voids behind the sloped rigid insulation was stuffed lightly with fiberglass insulation batts. Tanks were painted flat black, no fancy solar coatings then. Box faced due south and inclined a bit steeper than sun equinox angle, a tad favoring winter angle. Box had a ply lid that was also rigid insulated. A few times a year I'd adjust the angle of the lid at open position to gain the most reflection I could get from the lid foil faced insulation.

Operation was merely open the lid when the sun hit the box in the morning and close the lid at night. Lid opening in our case was easy as the box was mounted in front and below our front deck on the hillside home site. Two ropes were tied to the deck handrail that were lengthened/shortened to make the lid angle adjustment.

This system was at our year-round home at 3000ft elevation in the Cascade mountains of southern Oregon in the eighties. We lived in a fairly steep river valley meadow so we had mountains east and west that blocked early morning, late afternoon sun. Still, the system produced 100% of all hot water needs for two, including clothes washing, for eight/nine months a year. The remainder of the year it was used in "good" weather but mostly, during the rain/snow season, used as a pre-heater to the coils run through the wood cookstove.

As I recall the total cost of the heater was in the range of $135 -$150 around 1981-82. A day or so each to design/draw plan, build, install. We ran this system about 7-8 years until we moved.

BTW - At the no-grid home, early 70's, refrigeration was a few crocks in the spring overflow flume that ran underneath the house and ran off in a waterfall in front, below, the south porch. Later we had an older propane refrigerator but I never got it running well. Water (of course) was gravity flow spring water. Lights were propane and kerosene lamps; we liked the Aladdin lamps (light equivalent to a propane but silent!). Stove was wood cookstove and a propane stove top for the hottest part of the summer. Music was homemade or a car stereo radio/cassette deck hooked to a 12v battery I charged every couple weeks in the truck. No TV. Space heating was wood. Total annual utility bill was a couple fills of the 20 gal propane tank (at something ridiculous like $.70 or so a gallon!) and about ten gallons of kerosene. Maybe $80 to $100 max a year. We were snowed in for about 4 months a year; I was a timber faller in the summer. then a carpenter. Yes, we had a flush toilet; this was a classy shack!

 

[jdmar]

Absolutely fantastic post. I appreciate all the pics and the links everyone has provided. I have an efficient house (SIPS) but no solar/wind/water power yet. I think I need to get going!
Peter

 

[hayden]

My experience with truck deliveries is that they are always a bit of a fiasco. Today was no exception.

The good news is that the batteries arrived - all 3900 lbs of them - and they are safely on the ground. The driver found our house, which is no small feat, and he brought a truck small enough to get in AND get turned around to get out again. The truck had a lift gate, and he had a pallet jack on-board to maneuver the pallets to the back of the truck and within reach of my tractor. Doesn't sound too bad, does it?

This first problem was that his pallet jack was just a touch too wide to get under the pallets. It would get in an inch or two and wedge on the sides against the pallet frame. I now know an industry that would benefit from standardization - pallet manufacturers. I though the world had already learned this lesson, but apparently not.

So, we messed around for about an hour with different combinations of tow straps, chains, and lifting straps attached to my tractor trying to pull these pallets (and contents too!) out to the back of the truck. It was pretty comical. We finally got the first pallet out by ramming the jack far enough into the pallet that we could lift most of the weight and drag it back.

I was then able to fork it with my tractor's pallet forks, which fortunately are adjustable. This is where I expected trouble since my loader is rated at around 1800-1900 lbs depending on how far in front you are lifting, and each pallet weighed 315 lbs x 6 + the pallet and packing. That's about 1900 lbs if my math is right, and I was worried that the loader wouldn't lift the load and that I'd have to unload one battery at a time. It turns out that the loader CAN lift a 1900 lbs pallet, but the rear wheels can't stay on the ground at the same time. So off I went in search of an accessible, heavy, and quick to attach 3PH implement to act as a counter weight. My rake was accessible and quick to attach, but not the heaviest thing around, but I tried it anyway. Good news, it was enough. I was able to fork the pallet off the back of the truck and get it out of the way. It was definitely right at the limit of the loader. Depending on the position, I could curl but not lift, or lift but not curl.

That was the easy one. The next pallet was partially behind another load so we didn't have a straight pull with the tow strap. Plus, the batteries we way over to one side on the pallet and even a little off one side, so it was even harder to un-weight it enough to move it. But with lots of shoving, jacking, pulling and cussing, we got it to the back of the truck. Now the adjustable forks on the tractor came in handy again because I was able to offset them to compensate for the off center load on the pallet and get the load centered for the tractor. With the loader at it's limits, the last thing I wanted was to tip the tractor over and spill 60 gal of sulfuric acid all over the place.

Finally, two pallets on the ground and covered with a tarp.

You might ask, "why no pictures". Did I mention that it was pouring rain the whole time?

 

[tommu56]

hayden

At least you could get them delivered when I wanted my L16's I had to drive an hour south load them by hand then drive 300 more miles north and unload them by hand. Now I just need more panels Iam at only 250 watts and last week my wife was up there all week with out any sun and batteries were down to 80% when I got there to fire up generator .

tom

 

[schmism]

any intrest in selling your old 4K inverter?

Will it grid tie?

Ive got materials for my otherpower 12' wind turbine aquired, and plan to have it installed by fall. I want to add about 600w of solar in addtion.

mine would be grid tied as i dont want to fuss with rewireing the house to split circuits between offgrid and on grid....

My goal is to produce 50% of our power requirements, and have a long term (4 day +) backup, reduced comsuption durring this period, solution as well as 100% short term needs, measured in hrs not days. Id say we loose power for 2-4 hrs at least once a month.

may not sound bad, but when you came from a location in st louis that lost power twice in 8 years for about an hr even when entire parts of the city were out due to storms, its a lot.

 

[hayden]

any intrest in selling your old 4K inverter?

Will it grid tie?

Yes to both questions, but I have a tentative buyer for most if not all of my old system. If it falls through, I'll let you know.

 

[varmint]

Once again, TBN provides a great surprise discovery: this thread! About the only thing I can add is this: your diesel generator can provide a good source of heat as well as electricity- I once meet some folks who had a big CNC machine operation on their family farm, which had utiltiy power, but not the 3 phase that their CNC required. So, since they were too far from the needed 3 phase to afford installation, they solved the problem with a Cat. diesel generator. Being in the NE, the waste heat was put to good use most of the time.
We have a horse barn with the perfectly oriented roof for solar panels, so I am getting interested in installing a 4-5KW (?) system, not because we have to, but because it's the right thing to do. We already drive a hybrid, sold our pickup truck because I hardly needed it, use CFBs, gas demand water heater, dual flush toilets, etc., and seems like solar would be great, grid-tied of course. Just wish there was a way to make our old farmhouse tighter. Really enjoyed your posts, and look forward to more!